We use experimental evolution to study the process of evolution in ‘real-time’. The small size and fast generation times of microorganisms allows replicate populations to be propagated under controlled environmental conditions for thousands of generations. Large population sizes means that many mutations can be sampled by evolving populations, so that evolution can be rapid.Because microbes can be cryopreserved, entire populations can be saved as a living “fossil record” to be resuscitated later to investigate changes of key parameters such as fitness or diversity.

Experimental evolution using microbial systems has led to tremendous insight across general (e.g., understanding factors influencing the repeatability of evolution) and specific (e.g., the mechanisms contributing to bacterial specialization on particular resources) questions.